Truckers can't rely on GPS alone

Aside from the use of GPS devices, which often lead them astray, why can't truckers be made aware that certain Westchester roadways designated as parkways that also include the name of a waterway, i.e. Bronx River Parkway, Hutchinson River Parkway, Sprain Brook Parkway, Saw Mill River Parkway, can only be used by passenger cars?